The biosynthesis and secretion of penicillinase by Bacillus licheniformis and of the glycoprotein enzymes invertase and alkaline phosphatase by Saccharomyces yeasts will be studied to determine the various steps in enzyme secretion by microorganisms and their relation to the process in animal cells. We will characterize the N-terminal extension on the membrane penicillinase and determine the basis for its unusual hydrophobicity. The function of a hydrophobic penicillinase-binding protein in the membrane will be assessed, especially by cross-linking under various conditions. We have shown that a mutation in the structural gene for invertase produces ts forms of both the glycoprotein and carbohydrate-free small forms; hence, the apparent absence of cysteinyl residues in the small form will be re-examined. Cloning of the invertase gene is underway. The isolated DNA will be used to produce probes for mRNA to permit measurement of changes in mRNA levels during regulation.